Jika 2x + 3y = 12 dan x – y = 1 maka nilai 2x + 3y = …

2x+3y = 12 [×1]
x-y = 1 [×2]

2x+3y = 12
2x-2y = 2
_________-
5y = 10
y = 10/5
y = 2

subtitusi y=2
2x+3y=12
2x+3(2)=12
2x+6=12
2x= 12-6
2x= 6
x= 6/2
x = 3

2x+3y=2(3)+3(2)
= 6+6
=12